Vacuum cleaners applied to expel the air from sealed bag, may reduce the bulky, fluffy volume of the received objects. Being a well-known technique to store the objects, such as clothes, quilts, occupied space can be reduced so as to inhibit bacteria growth. In practice, a valve is applied to expel the dead air from the bag without flowing back thereto. Thus one-way valve plays a role when using a sealed bag for receiving objects. About the structure of one-way valve, we can see five US patent documents about the one way valve as following: 1. U.S. Pat. No. 6,604,634 entitled “receiving bag with enhanced airtight effect” issued to the inventor of the present invention Fu-Long Su on 12 Aug. 2003. 2. U.S. Pat. No. 5,931,189 entitled “one way valve for use with vacuum cleaner attachment” issued to Sweeny et al. on 3 Aug. 1999. 3. U.S. Pat. No. 5,480,030 entitled “reusable, evacuable enclosure for storage of clothing and the like” issued to Sweeny et al. on 2 Jan. 1996. 4. U.S. Pat. No. 5,450,963 entitled “air removal device for sealed storage container” issued to James A. Carson on 19 Sep. 1995. 5. U.S. Pat. No. 6,408,872 entitled “evacuable container one-way valve with filter element” issued to Skeens et al. on 25 Jun. 2002.
Aforesaid one-way valve of prior arts has some drawbacks as following:
1. One-way valve of U.S. Pat. No. 6,604,634 is manufactured through a more complex process to form a valve, which is also cost-inefficient.
2. U.S. Pat. Nos. 6,604,634, 5,931,189, and 5,480,030 show a valve seat is covered by a cap, before expelling air from the bag, the cap must be removed from the valve seat. After expelling air, the cap is re-capped over the valve seat. In practice the separated cap is easily to lose. Further, the procedures of frequently removing and re-capping of the cap to the valve seat are also inconvenient for the users.
3. Aforesaid cap is capped over the valve seat projected out from the sealed bag. As the sealed bags are in the process of moving, stacking or storing, the caps are easily to drop, to lift by forces of impacting or pressing.
4. Aforesaid sealed bag is full of air, and the cap is screwed thereon. As an outer force is exerted to the bag, the bag is compressed, an air pressure is instantly and automatically increased in the bag, which is greater than a tension dynamically maintained by the closure between the cap and the valve seat, the closure will eject the cap to pop out.
5. Aforesaid valve seat has diaphragm made of elastic film. Supposed the cap is impacted or compressed by an outer force or a heavy stamping, because there has no instrument can be applied to buffer and fit the cap and diaphragm in position, so the diaphragm endured a larger force is pushed to move out of its location; the sealed mechanism of the diaphragm is therefore affected to minimize, to eliminate.
6. Aforesaid U.S. Pat. Nos. 6,604,634, 5,931,189, 5,480,030, 5,450,963, and 6,408,872, the diaphragm is made of silica gel or rubber, they are influenced by the density-dependent factors such as to expand when hot and to shrink when cold, especially a bit of shrinkage in the frigid zone, results in incomplete closure of the air pore or vent hole, the expelled air can be flowed back.
7. Aforesaid U.S. Pat. Nos. 5,450,963, and 6,408,872 has no cap over the valve seat, though it aims to simplify the structure of the valve, a little deformation or damage happened to the diaphragm results in incomplete closure of the air pore or vent hole; and then the expelled air is flowing back. Let alone the diaphragm has a limited endurance test duration in unison with the elastic valve, and the density dependent factors such as to expand when hot and to shrink when cold affect the same diaphragm. Without a cap to adjust the pressure exerted to the diaphragm, the mechanism of the valve is still imperfect.